Allardyce has accused Kean of slander in the video, secretly filmed by Blackburn fans in a bar in Hong Kong during the club’s pre-season tour last year.

The video features Kean in an explicit rant at the way the former Rovers boss treated him.

Kean was Allardyce’s number two at Blackburn and Allardyce has been advised by his solicitors to sue both Kean and his previous employers.

A statement on behalf of Allardyce read: ‘He has issued legal proceedings but is unable to comment further.’

In the video, Kean claims credit for discovering defender Phil Jones, now at Manchester United, and questions the honesty of Allardyce.

When asked by the fans if he still speaks to Allardyce, Kean replied: ‘I haven’t spoken to him, he mullered me so I said f*** him.

‘I worked my b***s off for him and then he had a go at me so f*** him.’

Kean also claimed that Blackburn would be in the Premier League’s top half and win the Carling Cup with him in charge. They instead finished last season trophyless in the bottom three, and were relegated to the Championship.